Universal serial bus and method for transmitting serial clock and serial data signals during power-saving mode

1. A universal serial bus with a power-saving mode, comprising: a universal serial bus driving transceiver, comprising a first differential data signal terminal and a second differential data signal terminal; a serial transceiving port, comprising a serial clock signal terminal and a serial data signal terminal, which are coupled to the first differential data signal terminal and the second differential data signal terminal, respectively; and a universal serial bus core logic, coupled to the universal serial bus driving transceiver and the serial transceiving port, wherein when under a normal operational mode, the first and the second differential data signal terminals are driven for transceiving differential data signals; when under a power-saving mode, the serial clock signal terminal and the serial data signal terminal are driven for transceiving a serial clock signal and a serial data signal.

2. The universal serial bus with the power-saving mode of claim 1 , wherein the universal serial bus core logic is a universal serial bus host core logic.

3. The universal serial bus with the power-saving mode of claim 2 , wherein when the universal serial bus host core logic has detected a connection of a universal serial bus peripheral, the universal serial bus host core logic transmits an inquiry command for inquiring whether or not the universal serial bus peripheral supports the power-saving mode, and if the universal serial bus peripheral supports the power-saving mode, the power-saving mode is activated.

4. The universal serial bus with the power-saving mode of claim 2 , wherein when under the power-saving mode, the universal serial bus host core logic adjusts a frequency of the serial clock signal according to a request of data transmission.

5. The universal serial bus with the power-saving mode of claim 2 , wherein if there is no request of data transmission, the universal serial bus host core logic stops transmitting the serial clock signal.

6. The universal serial bus with the power-saving mode of claim 1 , wherein the universal serial bus core logic is a universal serial bus peripheral core logic.

7. The universal serial bus with the power-saving mode of claim 6 , wherein when receiving an inquiry command from a universal serial bus host, the universal serial bus peripheral core logic responds that the universal serial bus peripheral supports the power-saving mode, and is off-line and then reconnected again for operating the power-saving mode.

8. An operating method for a universal serial bus, adapted to combine a universal serial bus peripheral with a power-saving mode and a universal serial bus host with a power-saving mode to operate in a power-saving mode, the method comprising: transmitting an inquiry command from the universal serial bus host for inquiring whether or not the universal serial bus peripheral supports the power-saving mode; responding the inquiry command by the universal serial bus peripheral that the power-saving mode is supported, the universal serial bus peripheral being off-line and then reconnected for operating the power-saving mode; and switching the universal serial bus host to the power-saving mode; wherein under the power-saving mode, the universal serial bus host and the universal serial bus peripheral communicate by a serial clock signal and a serial data signal, wherein the serial clock signal is provided by the universal serial bus host, and the universal serial bus host core logic adjusts a frequency of a serial clock signal according to a request of data transmission and the universal serial bus host core logic stops transmitting the serial clock signal if it is indeed that there is no request of data transmission.